1. Technical Field
This invention generally relates to internal combustion engines and more specifically relates to internal combustion engines having an orbital piston movement in which the pistons move in a toroidal path.
2. Prior Art
Internal combustion engines generally can be categorized into three primary types: reciprocating or bore and stroke, rotary, and turbine. Each of these three types is well established and has been continuously enhanced throughout their long lineages.
A reciprocating or bore and stroke engine is an internal-combustion engine in which the crankshaft is turned by pistons moving up and down in cylinders. Typically, for automotive use, a reciprocating engine is of the four-stroke variety, in which an explosive mixture is drawn into the cylinder on the first stroke and is compressed and ignited on the second stroke, work is done on the third stroke and the products of combustion are exhausted on the fourth stroke.
A rotary engine is an internal-combustion engine in which power is transmitted directly to rotating components. For automotive uses, the Wankel® engine used in Mazda® automobiles is a common example. In other words, a rotary engine is an internal-combustion engine having combustion chambers generally with a triangular shaped piston that oscillates as it rotates.
A turbine engine is an engine in which the energy in a moving fluid is converted into mechanical energy by causing a bladed rotor to rotate. A typical turbine engine will have a set of rotor blades that induce and compress air. Fuel then is added and ignited. The expanding hot combustion gases accelerate as they move through a set of turbine blades. The set of turbine blades is mechanically connected to the set of rotor blades, providing the power to make the set of rotor blades continue to spin and draw in fresh air. Broadly, a turbine is any of various machines in which the energy of a moving fluid is converted to mechanical power by the impulse or reaction of the fluid with a series of buckets, paddles, or blades arrayed about the circumference of a wheel or cylinder.
Internal combustion engines of each of these three general types have their advantages and disadvantages. A reciprocating engine has a mature design, relatively low cost, moderate power to weight ratio, moderate size, and moderate fuel efficiency. A rotary engine has a less mature design, moderate cost, higher power to weight ratio, small size, and moderate to low fuel efficiency. A turbine has a mature design, high cost, high power to weight ratio, large size, and low fuel efficiency.
Thus, it can be seen that a need exists for an internal combustion engine combining at least some of the advantages of the three general types of internal combustion engines. For example, a preferred engine may have the relatively low cost of manufacture of a reciprocating engine and the high power to weight ratio and small size of a rotary engine, along with a higher fuel efficiency not generally found in any internal combustion engine. The present invention is directed to such a preferred engine.